1. Field of the Invention
The invention relates to a heterocyclic derivative, and more particularly to a quinoxaline derivative used in an organic light-emitting diode.
2. Description of the Related Art
Organic light-emitting diodes (OLED) are popularly applied in flat panel displays and flexible displays due to their light weight, thin profile, self-illuminating, low power consumption, no backlight requirement, wide viewing angle, rapid response time and capability to fabricate on flexible substrate. Meanwhile, conventional electron transport material has a carrier mobility which is 1% that of hole transport material and has low thermal stability, resulting in low luminescent efficiency and a short lifespan. Also, the charge consumption of electron transport materials is 35.96%, while that of a light-emitting layer is 39.8%. Thus, development of an electron transport material with high carrier mobility which may be used in OLEDs is desirable.
Accordingly, Alq3, which has superior film-forming properties, have been developed and applied in electron transport materials and host materials. Additionally, metal (Be, Al, Zn) complexes, 1,2,4-triazoles (TAZ) derivatives, fluorine-containing compounds and silicon-containing compounds have also been developed and applied in electron transport materials due to their higher carrier mobility and Tg when compared to Alq3. However, carrier mobility, thermal stability and current density of the materials are still insufficient for use in electron transport materials.